4 ms·

Some of the perf gains on the M1 are due to hardware support for TSO (total store ordering), which doesn't exist on the latest/highest-end Qualcomm chip, hence

Some of the perf gains on the M1 are due to hardware support for TSO (total store ordering), which doesn't exist on the latest/highest-end Qualcomm chip, hence the Windows support needs to insert many more barriers to emulate TSO. This likely has a significant impact on emulated performance. At least the x86 (32-bit) emulation relied entirely on JIT compiling its emulated code, instead of doing anything AOT. _However_, it cached the JIT'd code so in practice it was a first-run cost, similar to the situation on macOS.

saagarjha 6y ago
I believe windows elides TSO guarantees when it thinks they aren't necessary. This should usually work out all right–only a small amount of code usually cares very much about memory ordering.
- asveikau 6y ago
  That seems like a very difficult task to determine when it matters.